Industrial and commercial batch and continuous process manufacturing systems often use equipment with rotational components for product conveyance and fabrication. It is critical to insure moving equipment in the process stream is functioning as required such that dependent upstream machine(s) may safely and correctly deliver product to successive processing lines or equipment. The attachment of sensors that monitor the rotational movement and speed of process equipment is commonplace where incorrect speed, or a full stop of rotation, indicates a material delivery fault that must be addressed. The managing of speed faults may be provided by hardwired interlock connections, or by process computer controlled decision making, which ultimately affect the operation of dependent equipment in the process stream.
Current rotational monitors are normally comprised of two required components: a target fixture and an externally powered sensor/detector device. Two typical arrangements are:
1) a target fixture of ferrous or magnetic construction that is attached to the rotating component, and a separate hardwired proximity sensor using inductive or Hall Effect circuitry to detect the target.
2) a target fixture attached to the rotating component that is fabricated to provide one or more optical occlusions that are detected by a separate hardwired photo-sensitive sensor.
There are two inherent problems with these monitor types:
1) The sensor must be mounted to a stationary reference fixture separately from the rotating target. The spacing (gap) between the sensor and target is critical. This configuration is intolerant of deviations to the gap distance and the gap is subject to blockage by debris.
2) When one or more instances of conventional monitor installations are used, each instance requires the user to provide and distribute dedicated operating power and signal wiring to the monitor locations to integrate the sensor(s) into an overall control system.